THE INFLUENCE SUNLIGHT EXPOSURE TOWARDS NITRATE LEVELS IN WATER SPINACH (IPOMEA AQUATICA FORSSKAL)
From the point view of food safety, the presence of nitrate in edible vegetables is a source of chemical hazard and hence its intake should be controlled. Intake control of nitrate can be performed by means of minimization of nitrate content in this vegetables. Nitrate content in vegetable was repo...
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| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/78847 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | From the point view of food safety, the presence of nitrate in edible vegetables is a source of chemical hazard and hence its intake should be controlled. Intake control of nitrate can be performed by means of minimization of nitrate content in this vegetables. Nitrate content in vegetable was reported to be influenced by exposure to sunlight. The nitrate content decreases with increasing sunlight intensity and exposure dæration. The aim of the research was to study the influence of exposure duration of sunlight under common sunny day on nitrate content in water spinach (Ipomea aquatika Forsskal) as one of vegetable widely consumed by population. Water spinach was planted in a pot size 30 cm x 80 cm with total number of four pots. Compost consist of 24.1% C-organic, 1.21% of total nitrogen, 1.79% of diphosphorus pentoxide and 1.84% of dipotassium oxide were applied. Plants exposed to light for 12 hours between 06.00 till 18.00. Every 2 hours samples were collected and stored in a refrigerator. Nitrate contents were determined spectrophotometrically at 410 nm. Calibration curve of nitrate gave a regression equation of y = 0.2147x — 0.0137, with a quadratic of conelation coefficient (F) of 0.9973. Limit of detection and quantification were 0.4252 and 1.4174 gg/ml, within and inter-day precisions stated as coefficient of variance (CV) were determined in three different days with the CV values of 3.35, 2.35 and 1.07% for within day precision and 3.83% for inter-day precision. The recovery of nitrate standard addition at the concentration levels of 24.0, 48.0, 72.0 and 96.0 ppm were 86.3, 70.5, 85.7 and 97.4%, respectively. Nitrate levels in water spinach samples from three different days were in the range of 513.8 to 901.1 mg/kg. The lowest -level of nitrate was observed in the samples collected at 12.00 which was 513.8 mg/kg. On the contrary, the highest level of nitrate was observed in the samples collected at 06.00 which was 901.1 mg/kg, while the average level of nitrate in the water spinach was 705.1 mg/kg. Based on overall results, it was concluded that the duration of sunlight exposure significantly affects the nitrate levels in water spinach samples.
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